From Kotaku:
"Sources close to Ubisoft tell me that the game is indeed coming this year (although I'm hearing December 11th), so it looks like Sony will at least get one third party exclusive out the door. Still, I bet the house that Ken Kutagari built is still kicking itself that it didn't lock up Assassin's Creed as a PS3 exclusive, especially with early review scores like a 9.5 from Game Informer."